Annotation of gforth/vmgen-ex/mini-inst.vmg, revision 1.1

1.1     ! anton       1: \ mini.inst is generated automatically from mini-inst.vmg and mini-super.vmg
        !             2: \ example .vmg file
        !             3: 
        !             4: \ Copyright (C) 2001 Free Software Foundation, Inc.
        !             5: 
        !             6: \ This file is part of Gforth.
        !             7: 
        !             8: \ Gforth is free software; you can redistribute it and/or
        !             9: \ modify it under the terms of the GNU General Public License
        !            10: \ as published by the Free Software Foundation; either version 2
        !            11: \ of the License, or (at your option) any later version.
        !            12: 
        !            13: \ This program is distributed in the hope that it will be useful,
        !            14: \ but WITHOUT ANY WARRANTY; without even the implied warranty of
        !            15: \ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
        !            16: \ GNU General Public License for more details.
        !            17: 
        !            18: \ You should have received a copy of the GNU General Public License
        !            19: \ along with this program; if not, write to the Free Software
        !            20: \ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
        !            21: 
        !            22: 
        !            23: \ WARNING: This file is processed by m4. Make sure your identifiers
        !            24: \ don't collide with m4's (e.g. by undefining them).
        !            25: 
        !            26: 
        !            27: \ comments start with "\ "
        !            28: 
        !            29: \ stack definitions:
        !            30: \E stack data-stack sp Cell
        !            31: 
        !            32: \ stack prefix definitions
        !            33: \E inst-stream stack-prefix #
        !            34: 
        !            35: \ type prefix definitions:
        !            36: \E s" Cell"   single data-stack type-prefix i
        !            37: \E s" char *" single data-stack type-prefix a
        !            38: \E s" Inst *" single data-stack type-prefix target
        !            39: 
        !            40: \ simple VM instructions:
        !            41: add  ( i1 i2 -- i )
        !            42: i = i1+i2;
        !            43: 
        !            44: sub ( i1 i2 -- i )
        !            45: i = i1-i2;
        !            46: 
        !            47: mul ( i1 i2 -- i )
        !            48: i = i1*i2;
        !            49: 
        !            50: and ( i1 i2 -- i )
        !            51: i = i1 & i2;
        !            52: 
        !            53: or ( i1 i2 -- i )
        !            54: i = i1 | i2;
        !            55: 
        !            56: lessthan ( i1 i2 -- i )
        !            57: i = i1<i2;
        !            58: 
        !            59: equals ( i1 i2 -- i )
        !            60: i = i1==i2;
        !            61: 
        !            62: not ( i1 -- i2 )
        !            63: i2 = !i1;
        !            64: 
        !            65: negate ( i1 -- i2 )
        !            66: i2 = -i1;
        !            67: 
        !            68: lit ( #i -- i )
        !            69: 
        !            70: drop ( i -- )
        !            71: 
        !            72: print ( i -- )
        !            73: printf("%ld\n", i);
        !            74: 
        !            75: branch ( #target -- )
        !            76: SET_IP(target);
        !            77: 
        !            78: zbranch ( #target i -- )
        !            79: if (i==0) {
        !            80:   SET_IP(target);
        !            81:   TAIL;
        !            82: }
        !            83: 
        !            84: \  The stack is organized as follows:
        !            85: \  The stack grows downwards; a stack usually looks like this:
        !            86: 
        !            87: \  higher addresses
        !            88: \  --------------------- bottom of stack
        !            89: \     locals of main
        !            90: \     return address (points to VM code after call)
        !            91: \  +->oldfp (NULL)
        !            92: \  |  intermediate results (e.g., 1 for a call like 1+foo(...))
        !            93: \  |  arguments passed to the called function
        !            94: \  |  locals of the called function
        !            95: \  |  return address (points to VM code after call)
        !            96: \  +--oldfp                <-- fp
        !            97: \     intermediate results <-- sp
        !            98: \  ---------------------- top of stack
        !            99: \  lower addresses
        !           100: 
        !           101: \ The following VM instructions also explicitly reference sp and
        !           102: \ therefore may have to do something about spTOS caching.
        !           103: 
        !           104: call ( #target #iadjust -- targetret aoldfp )
        !           105: /* IF_spTOS(sp[2] = spTOS);*/ /* unnecessary; vmgen inserts a flush anyway */
        !           106: targetret = IP;
        !           107: SET_IP(target);
        !           108: aoldfp = fp;
        !           109: sp = (Cell *)(((char *)sp)+iadjust);
        !           110: fp = (char *)sp;
        !           111: /* IF_spTOS(spTOS = sp[0]); */ /* dead, thus unnecessary; vmgen copies aoldfp there */
        !           112: 
        !           113: return ( #iadjust target afp i1 -- i2 )
        !           114: /* IF_spTOS(sp[-2] = spTOS); */ /* unnecessary; that stack item is dead */
        !           115: SET_IP(target);
        !           116: sp = (Cell *)(((char *)sp)+iadjust);
        !           117: fp = afp;
        !           118: i2=i1;
        !           119: /* IF_spTOS(spTOS = sp[0]); */ /* dead, thus unnecessary; vmgen copies i2 there */
        !           120: 
        !           121: \ loadlocal and storelocal access stack items below spTOS, so we can
        !           122: \ ignore spTOS caching.
        !           123: 
        !           124: loadlocal ( #ioffset -- i )
        !           125: i = *(Cell *)(fp+ioffset);
        !           126: 
        !           127: storelocal ( #ioffset i -- )
        !           128: *(Cell *)(fp+ioffset) = i;
        !           129: 
        !           130: end ( i -- )
        !           131: /* SUPER_END would increment the next BB count (because IP points there);
        !           132:    this would be a problem if there is no following BB.
        !           133:    Instead, we do the following to add an end point for the current BB: */
        !           134: #ifdef VM_PROFILING
        !           135: block_insert(IP); /* we also do this at compile time, so this is unnecessary */
        !           136: #endif
        !           137: return i;
        !           138: 
        !           139: include(mini-super.vmg)

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